biofilm Articles
-
Biofilm Processes
The biofilm process is a process which uses a biofilm for the purposes of filtration, bioremediation or barrier formation. A biofilm is a complex and heterogeneous matrix of microorganisms attatched to and growing on a surface. Biofilms are most often found on solid substrates that are exposed ...
-
Dispersive transport in porous media with biofilms: local mass equilibrium in simple unit cells
In this work, we continue our study of upscaling biofilm processes in porous media from the pore scale to the Darcy scale. We adopt a continuum-level description of biofilms at the pore scale on the basis of work reported in Wood et al. (2002b). We upscale from the pore scale to the Darcy scale using the method of volume averaging and we predict the effective dispersion tensor with two- and ...
-
Effective dispersion in channelled biofilms
Heterogeneous biofilms may arise because of non-uniform biofilm growth. When considering multiple-scale problems involving biofilms, a direct simulation of the flow in the heterogeneous biofilm is not tractable. This calls for an averaged description of the flow and transport in such heterogeneous biofilms. This paper presents a theoretical derivation of the transport equations in such ...
-
An experimentally validated immersed boundary model of fluid–biofilm interaction
Biofllms are colonies of microorganisms that live on wetted surfaces in a matrix consisting of polysaccharides, proteins, and nucleic acids. According to the National Institute of Health (NIH), biofilms play a role in over 80 percent of microbial infections in the body and these infections are remarkably difficult to treat with antimicrobial compounds. The objective here is to understand and ...
-
Influence of the nature of hydrodynamic constraints on aerobic biofilms
The aim of this paper is to relate biofilm detachment to local hydrodynamics. Biofilm was submitted to erosion tests in three devices: a Couette Taylor Reactor (CTR) and two Stirred Reactors (SR) Without Baffles (WOB) and With Baffles (WB). Each device involved different hydrodynamics and different impacts on the biofilm detachment. In CTR, the detachment was significant in one specific zone on ...
-
The effect of flow velocity on the distribution and composition of extracellular polymeric substances in biofilms and the detachment mechanism of biofilms
Flume experiments were conducted to investigate the distribution and composition of extracellular polymeric substances (EPS) in biofilms and the detachment mechanism of biofilms grown under different flow velocity conditions. The results of biofilm growth kinetics showed that the growth trends were coincident with the logistic growth model. The growth kinetics parameters reached their maximum ...
-
Development of a simplified model for the fixed biofilm reactor
A simplified fixed biofilm model was developed to formulate the relationship between the substrate concentrations at both the entry and exit, at the biofilm–liquid interface and at the biofilm attached surface along with average substrate flux in the biofilm, substrate flux at the biofilm–liquid interface and effective biofilm thickness. The model considered the substrate mass transport ...
-
Fate of
Salmonella Typhimurium in laboratory-scale drinking water biofilmsInvestigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of ...
-
Numerical simulation of wrinkle morphology formation and the evolution of different Bacillus subtilis biofilms
Wrinkle morphology is a distinctive phenomenon observed in mature biofilms that are produced by a great number of bacteria. The wrinkle pattern depends on the mechanical properties of the agar substrate and the biofilm itself, governed by the extracellular matrix (ECM). Here we study the macroscopic structures and the evolution of Bacillus subtilis biofilm wrinkles using the commercial finite ...
-
A framework for good biofilm reactor modeling practice (GBRMP)
A researcher or practitioner can employ a biofilm model to gain insight into what controls the performance of a biofilm process and for optimizing its performance. While a wide range of biofilm-modeling platforms is available, a good strategy is to choose the simplest model that includes sufficient components and processes to address the modeling goal. In most cases, a one-dimensional biofilm ...
-
Microbial indicators in natural biofilms developed in the riverbed
Microbial indicators such as heterotrophic bacteria, total coliforms, and Escherichia coli in naturally developed riverbed biofilms were investigated. Pebbles covered with natural biofilm were sampled directly from the riverbed at sampling stations ranging from the upstream region within a quasi-national park to the midstream in the urban district. Heterotrophic bacteria densities in biofilm ...
-
Heavy metal tolerance and removal potential in mixed-species biofilm
The aim of the study was to examine heavy metal tolerance (Cd2+, Zn2+, Ni2+ and Cu2+) of single- and mixed-species biofilms (Rhodotorula mucilaginosa and Escherichia coli) and to determine metal removal efficiency (Cd2+, Zn2+, Ni2+, Cu2+, Pb2+ and Hg2+). Metal tolerance was quantified by crystal violet assay and results were confirmed by fluorescence microscopy. Metal removal efficiency was ...
-
Biofilm carrier migration model describes reactor performance
The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved ...
-
Evaluation of biofilm performance as a protective barrier against biocorrosion using an enzyme electrode
Sulfide is known to be an important factor in microbiologically influenced corrosion (MIC) of metals and concrete deterioration in wastewater treatment structures and sewer pipelines. A sulfide biosensor was used to determine the effectiveness of Escherichia coli DH5α biofilm as a protective barrier against MIC. The biofilm was shown to be effective in protecting surfaces from sulfide and helping ...
-
Effect of biofilm on colloid attachment in saturated porous media
Biofilm plays an important role in controlling the transport of colloids in a porous media. Biofilms are formed when micro-organisms come in contact with substrates, and are able to attach and grow with availability of nutrients. The microorganisms get embedded in a matrix of the substrate and extracellular polymeric substances which are responsible for the morphology, physico-chemical ...
-
Contribution of hydrodynamic characteristics on the performance of an aerobic biofilm conical fluidized bed
The performance of a conical fluidized bed (TFB) bioreactor, including the biofilm thickness, microbial space density, microbial cell matrix and its efficiency for COD degradation at a bed expansion ratio of 14 to 90%, was studied and compared with a cylindrical fluidized bed (CFB) bioreactor. The hydrodynamic characteristics of the TFB, especially the internal-circulation of bioparticles ...
-
Magnetic resonance imaging of structure, diffusivity, and copper immobilization in a phototrophic biofilm
Magnetic resonance imaging (MRI) was used to spatially resolve the structure, water diffusion, and copper transport of a phototrophic biofilm and its fate. MRI was able to resolve considerable structural heterogeneity, ranging from classical laminations 500 µm thick to structures with no apparent ordering. Pulsed-field gradient (PFG) analysis spatially resolved water diffusion coefficients which ...
-
How do stream organisms respond to, and influence, the concentration of titanium dioxide nanoparticles? A mesocosm study with algae and herbivores
The biologically active properties of many nanomaterials, coupled with their rapidly expanding production and use, has generated concern that certain types of nanoparticles could have unintended impacts when released into natural ecosystems. In the present study, the authors report the results of an experiment in which they grew three common species of stream algae as monocultures and together as ...
-
Fluctuation of densities of bacteriophages and
Escherichia coli present in natural biofilms and water of a main channel and a small tributaryFluctuation of bacteriophage and Escherichia coli densities in naturally developed riverbed biofilms were investigated for a 1-year period. E. coli ranged from 1,500 to 15,500 most probable number (MPN)/100 mL and from 580 to 18,500 MPN/cm2 in the main channel in the river water and biofilms, respectively. However, the fluctuations were much greater in the tributary, ranging from 0.8 to 100 ...
-
The role of homoacetogenic bacteria as efficient hydrogen scavengers in microbial electrochemical cells (MXCs)
We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen ...
Need help finding the right suppliers? Try XPRT Sourcing. Let the XPRTs do the work for you